How colonization of the Americas killed 90 percent of their Indigenous people – and changed the climate

There is now scientific evidence that links climate change to the first encounter and the cumulative destruction of Indigenous societies.

Image Credit: Universal History Archive/UIG/Getty Images

A Short Account of the Destruction of the Indies in 1552. He even described “more than thirty other islands in the vicinity of San Juan are for the most part and for the same reason depopulated, and the land laid waste. On these islands I estimate there are 2,100 leagues of land that have been ruined and depopulated, empty of people.”

Now a new study adds hard data, documenting the global cost of colonialism.

Why does it matter? Because the invasion of the Americas changed everything on the planet. There was a death rate of more than 90 percent of the people (labeled “depopulation” in the scientific report). At that time, the Indigenous population of the Americas was 10 percent of the world’s population and home to the largest and most complex cities.

The study also raises new questions about the “anthropogenic” or the human impact on nature and what that might mean for climate change policy in the decades ahead.

The paper “Earth System Impacts of the European Arrival and Great Dying in the Americas after 1492” was written by four geographers from University College London, Alexander Koch, Chris Brierley, Mark M. Maslin and Simon L. Lewis. The peer-reviewed article was published by Quaternary Science Reviews.

The study shows how Europe thrived after the genocide. “The really weird thing is, the depopulation of the Americas may have inadvertently allowed the Europeans to dominate the world,” co-author Mark Maslin told the BBC. “It also allowed for the Industrial Revolution and for Europeans to continue that domination.”

“Human impacts prior to the Industrial Revolution are not well constrained,” the authors wrote. “We investigate whether the decline in global atmospheric CO2 concentration by 7 to 10 ppm in the late 1500s and early 1600s, which globally lowered surface air temperatures by 0.15 degrees C, were generated by natural forcing or were a result of the large-scale depopulation of the Americas after European arrival, subsequent land use change, and secondary succession.” The researchers examined ice cores from Antarctica, measuring the atmospheric gases, including carbon dioxide, that were trapped centuries ago. Even though the global shift in temperature was tiny, only fifteen-hundredths of a degree, that was enough to lead to colder temperatures worldwide that resulted in colder summers and crop failures.

The paper explores a big question: Did the invasion and depopulation of the Americas in the 16th and 17th centuries result in the decline in temperatures, the Little Ice Age? And was that a result of “natural forces” or because of the “large-scale depopulation of the Americas after European arrival, subsequent land use change and secondary succession.”

The evidence is complicated. The Indigenous Americas went through a rapid and dramatic shift; a “before contact” and “after contact” story. But the problem is that the evidence was “only documented in the decades after European contact.” So the scientists looked at indirect methods to calculate a hemispheric estimate.

The first problem was trying to figure out how many people lived in the Americas. In Mexico, for example, the Europeans first arrived in 1519, but the first census took place in 1568, and other documentary evidence starts around 1540. That population evidence includes tributes, the size of armies, and settlement infrastructure.

Looking at all of the evidence available today, the University College London team concluded that the Indigenous population reached more than 60 million people before contact. That would have been about 10 percent of the world’s population, and the cities in the Americas would have been among the most populous on the planet. In less than 100 years that Indigenous America’s population was reduced to 5 or 6 million people; a population decline that exceeded 90 percent, the Great Dying.

The scientists calculated how such a rapid population decline would change agriculture (think of what it took to feed 60 million people) and land. This is what happened when farmland became forest and jungle. The scale of “regrowth” was huge, roughly a land mass twice the size of Colorado.

The scale is significant because Indigenous land use was so widespread before European arrival, particularly in Mexico, Central America, Bolivia, and the Andes, where terraced fields and irrigated agriculture were common. “The uptake of carbon on the abandoned anthropogenic lands after European contact may have been large enough to impact the atmospheric CO2 record,” the study says.

“To put that in the modern context, we basically burn [fossil fuels] and produce about 3 ppm per year. So, we’re talking a large amount of carbon that’s being sucked out of the atmosphere,” Maslin told the BBC. “There is a marked cooling around that time [1500s/1600s] which is called the Little Ice Age, and what’s interesting is that we can see natural processes giving a little bit of cooling, but actually to get the full cooling – double the natural processes – you have to have this genocide-generated drop in CO2.”

The authors say their study shows that the “global carbon budget of the 1500s cannot be balanced until large-scale vegetation regeneration in the Americas is included. The Great Dying of the Indigenous Peoples of the Americas resulted in a human-driven global impact on the Earth system in the two centuries prior to the Industrial Revolution.”

This study for Indian Country has implications beyond history.

One problem is how to quantify the impact of climate change on tribal communities. As the most recent National Climate Assessment reports: “The literature currently lacks studies that attempt to quantify and/or monetize climate impacts on Indigenous economies or economic activities.”

What if that thinking is too small? Scientific evidence links climate change to the first encounter and the cumulative destruction of Indigenous societies. Should there be an accounting? How would that work? Would the balance of accounts be broadened to include other industrial societies in Europe as well as the United States itself?

The study also raises questions about climate change policy. As one of the authors, Chris Brierley, told the BBC, “There is a lot of talk around ‘negative emissions’ approaching and using tree-planting to take carbon dioxide out of the atmosphere to mitigate climate change. And what we see from this study is the scale of what’s required, because the Great Dying resulted in an area the size of France being reforested and that gave us only a few parts per million. This is useful; it shows us what reforestation can do. But at the same, that kind of reduction is worth perhaps just two years of fossil fuel emissions at the present rate.”

Indeed, the scale of this history is daunting. In a Wakanda moment, two things come to mind.

First: Indigenous America was 10 percent of the world’s population before Columbus. If that were true today, there would be 700 million in the Indigenous world. Imagine that.

Second: We need to change the way we teach urban history. The great cities of the world were already here, both in terms of population and sophistication. Imagine the scale of feeding a largely urban population of 60 million people with terrace farms, canals, constructed lakes – approaches that would look innovative today.


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